A couple of years ago, two journalist friends of mine spent an afternoon with Oscar Pistorius. For much of the time, they recall, Oscar was quiet and self-contained. And then, apropos of nothing, he told a story. He was driving on the outskirts of a black township, he said, when a dog ran under his wheels. In his rear-view mirror, he watched as it dragged itself off the road by its front legs, its hind legs useless to it now. Its back was clearly broken. He stopped and got out of his car to find that the dog's owner had come out on to the street, shouting, cursing, gesticulating. What to do? Oscar grabbed his gun, shot the dog through the back of the head and drove off.

On Valentine's Day 2013, when the world learned that Oscar Pistorius had shot Reeva Steenkamp dead through a closed bathroom door, this story no longer sounded the same. Before 14 February, the man in the tale my friends tell is a little inscrutable, too hard perhaps, and clearly a cowboy. In the end, though, he does use his gun to put an animal out of its misery. But now… Well, along with everything else Oscar has ever said and done, it takes its place in the biographical backdrop to an alleged murder.

So it is with all of the crazy tales about Oscar. They are legendary. Versions of them appeared periodically in the New York Times, in Wired, in New Scientist. The journalist arrives in Johannesburg to find that Oscar himself has come to the airport to meet him. There is no chauffeur; Oscar will drive. On the freeway, he clocks 250kmh while reading a text message from a girl who wants to spend the night with him. The journalist is scared; he suddenly remembers that last year Oscar almost killed himself in a speedboat accident.

Another such tale: at Oscar's home, over lunch, talk turns to guns and Oscar grabs his 9mm pistol and two boxes of ammunition. And now Oscar and the journalist are burning a trail to the firing range, because Oscar insists on teaching the journalist to shoot.

Before 14 February, these were the colourful trimmings of magazine profiles. Oscar's accomplishments were superhuman. He had licence to be a little crazy. Indeed, it was expected. But now… Well, a switch has been flipped and we are listening to these same stories in a very dark place.

Something odd happened to South Africa when news of Steenkamp's death broke. By nightfall, the billboards of Oscar Pistorius that dotted the country's cities had been removed. South Africa, which had loved Oscar unreservedly that morning, now hated him. And as it spat venom at Oscar, so it excoriated itself. In newspapers and on radio and television, South Africans kept confusing Oscar with the whole nation. Oscar was a symptom, it was said, of too many guns, of too much crime, of too much fear. He was a sign that men were out of control, that they were killing, beating and raping the women they ostensibly loved. Oscar was rotten and South Africa was rotten.

Otherwise level-headed people began insulting each other. A South African cabinet minister, Lulu Xingwana, told an interviewer that Afrikaner men were raised to believe that women and children were their property and thus theirs to kill. She recanted and apologised the following day. When one of the country's leading social scientists, Professor Rachel Jewkes, said in an interview that an overwhelming number of the black men she had surveyed aspired to sleep with many women, the former editor of South Africa's Sunday Times, Mondli Makhanya, denounced her as a racist. Tempers flared. The country's fuse shortened by the hour.

On one level, South Africa's response to Reeva Steenkamp's killing was insane. As ferociously as we may love or hate him, Oscar is a stranger to us. We do not know what his love of fast cars and speedboats means. Nor do we know why he so enjoys shooting guns. Most importantly of all, we do not know why he killed Steenkamp, and we probably never will. We can imagine and reimagine that moment as often and as fiercely as we like. We were not there. All we know is that he shot her through a closed bathroom door. The rest we are making up.

And even if we could know Oscar, what might the state of his being tell us about South Africa? If he was indeed murderously crazy, why on Earth should this make all South African men so?

And yet, on another level, South Africa's over-involved relationship with Oscar Pistorius makes the profoundest sense. To an uncanny extent, the story the country tells about him is precisely the story it likes to tell about itself. It is no wonder that the two have become confused.

As an infant, Oscar lost his legs. He not only went on to walk, and then to run, but he did so faster than the able-bodied. He appeared to have broken the barriers of human limitation. There was no accounting for him.

So with South Africa. Under apartheid, our souls were rotting. Many people were jailed and tortured and murdered by men in uniform. Street crowds threw tyres around people's necks and torched them alive on the wisp of an accusation. Ours was a country sick with rancour. It was expected to implode.

In 1994, as if by a miracle, we were reborn. Our capacity to make peace was celebrated the world over. Our president was the most-loved human being on Earth. The sun shone on us. The world marvelled at us. Legless, we had also sprinted faster than anyone. And so, when Oscar came along, we grabbed him and owned him. Oscar was South Africa and South Africa was Oscar. Our stories were the same.

And yet there was something horribly wrong with both stories, was there not? In the days after Steenkamp's death, an astute sports writer made a moving observation. "During his Olympic preparations in Italy," Gerald Imray wrote, "Pistorius pulled out his cellphone to show me pictures of his bleeding leg stumps, rubbed raw from the friction of pounding around the track on his blades… Until that moment, I hadn't fully realised what Pistorius went through every time he slipped on his prosthetic blades to compete or train. Not many people had, I guess." Pistorius did not like people to see him without his prosthetics, Imray observed. Once, after a race, he watched Pistorius slip off to a secluded part of the track to swap his racing blades for his everyday legs.

These quiet observations are far more telling than the fast cars and the guns. Oscar is no miracle. It is not magic that propels his speed. More likely it is rage; more likely it is memories of humiliation. So, too, with South Africa. We are no miracle. We, too, have had to grind our stumps raw. We, too, have had to bury our shame. And so, when we heard what Oscar had done, we felt something like deja vu. As if we always knew that his story was not quite right.

Three months before Oscar shot Steenkamp, a South African talkshow host, Redi Tlhabi, published a memoir about an episode in her childhood. Tlhabi is a uniquely post-apartheid phenomenon. It is not just her life history that makes her so – raised in apartheid-era Soweto, she has, like many successful black South Africans, moved to the suburbs where, a generation ago, the only black people were domestic servants. Listening to Tlhabi's radio show, everything that is new and lovely washes over you. She is clever and funny. When she laughs, you can hear the lightness in her soul. Her listeners span South Africa's divides – they are black and white, rich and poor, from townships and suburbs. Her magic is to connect all these people. Listening to her, one can imagine that we all live in the same country.

And then came Tlhabi's memoir, Endings & Beginnings: A Story Of Healing. In it, she was 11 years old, living in Orlando East, the heart of old, established Soweto. It was 1989. Her family was neither rich nor poor – they were respectable, educated Sowetans. She had recently lost her beloved, doting father. He was found murdered in the streets of their neighbourhood. Why, young Redi did not know.

There were gangsters in Orlando – young men who killed and died. Their funerals were spectacular occasions. The mourners would spin their cars and fire their guns into the air while Redi's neighbours "lined up as if they were watching a grand prix".

Respectable and upstanding, Redi's parents did not permit a gangster's name to be uttered in their home. Her mother had a cousin who was a gangster, but he was not allowed to visit and Redi was forbidden to speak to him. When, at the age of eight or nine, Redi told her father that she had run an innocuous errand for two members of the local gang, he beat her.

And, yet, if the gangsters in Redi's neighbourhood were not respectable, they were nonetheless admired. This was apartheid, after all, and to stand up to armed white men was to be godlike. The neighbourhood's most legendary gangster, a young man called Mabegzo, was said to have done terrible things to the police. According to one story, Mabegzo killed two policemen, pushed their bodies out of their vehicle and did wheel spins in the police car to entertain the crowd.

Redi had never met Mabegzo. But she was certain that she would know him the instant she saw him. The idea terrified her. How would she stop herself from making eye contact with him? For, should their eyes meet, she was certain that Mabegzo would rape her. Gently, artfully, Tlhabi dropped the theme of rape into the story of her childhood. "I was big for my age," she writes, "and while my classmates were still sitting with their legs apart, I couldn't afford to be so childlike and carefree. With breasts and hips budding by the age of 10, I often attracted the attention of much older boys and young men. When I ignored them, the word rape fell from their lips with ease while their friends and onlookers just laughed."

These threats were not idle. Rape was omnipresent. Once, Redi watched a group of young boys luring her drunken, middle-aged neighbour, Tokai, into an empty house. They assured onlookers that they were helping her home, even though they were walking in the opposite direction. "The next morning," Redi writes, "I heard that Tokai had been found naked on a street corner and some little boys had had sex with her – not raped her, simply had sex with her! People would say matter-of-factly that Tokai should stop drinking, but no one ever suggested that she deserved justice…"

That she might one day be raped was a piece of knowledge Redi carried under her skin. She had seen it happen to so many people around her. Her elders neither stopped it nor dared speak about it. Indeed, it was taboo even to mention it. It was something a girl must face alone.

This is the story South Africa is hiding from when it gets lost in Oscar's tale. The boy with no legs who ran faster than anyone – the half-ruined country that became the best. These stories are opiates. South Africa does not know how to love a country in which ordinary little girls expect to be raped. So it invents another country and talks of miracles. That is also why our love for Oscar turned so quickly to hate. We knew that the Blade Runner was not a real human being, just as we know that the South African miracle isn't really our country.

Radio host Redi Tlhabi dared ­reveal the country’s darkest secret: that girls grew up in the townships in fear of being raped. Photograph: Gallo Images/Getty Images

But the connection between Redi's story and Oscar's goes much deeper than that. Redi finally met the dreaded Mabegzo. Instead of raping her, he fell for her and she for him. Their love was chaste – he seemed to regard her as an angel to be protected from the world. And she was mesmerised by the fierceness of his care for her. Their enchanted, celibate courtship lingered for months until, one day, walking home from school, Redi saw Mabegzo's dead body in the street. He had been murdered by members of his own gang. In the ensuing two decades, he haunted Redi. The book is an attempt to excise him.

It is only when looking back from adulthood that Tlhabi understands what drew her and Mabegzo together. They recognised in one another a mutual brokenness. Redi was mourning her beloved father. And Mabegzo, well, he had been raised by a severe grandmother who'd concealed from him everything about his past, including his mother's identity. Why? Because, he gradually learned, through whispers and insinuations, he was a rape-child, and thus a source of terrible shame.

It is truly unusual for a South African book not only to confront everyday violence as nakedly as Redi Tlhabi has done, but to cut so sharply to its sources. What Mabegzo needed, really, was a loving mother. He had been robbed of one by denial and silence, by a collective turning away from what is painful. And, strange as this may sound, as Tlhabi describes Mabegzo, we begin to catch glimpses of another Oscar Pistorius. It is not just that Oscar and Mabegzo both had a maniacal love of fast cars and guns. It is not just that both were brutal on their bodies – as an adult, Tlhabi learns that Mabegzo trained with pleasureless determination every day. It is something else.

Reading Oscar's autobiography, Blade Runner, is a disconcerting experience because there is nobody there; one ends the book none the wiser as to who Oscar is or what happens inside him. There are nonetheless moments when we glimpse something of what it meant to be a boy with no legs. He tells us, for instance, that his prostheses triggered a disorder called neurofibromatosis – periodically, noncancerous tumours would grow on his stumps.

"They were terribly painful," he writes, "and caused my stumps to become hypersensitive, making any movement and particularly walking impossible for me. I went through patches where I could not leave the house for three or four months at a stretch. I would have to stay at home and study alone. I missed school terribly." Oscar does not have the internal reach to tell us what his stumps meant to him during those deprived and painful months. But one can begin to imagine.

There is another passage in Blade Runner worth mentioning – 14-year-old Oscar standing at the bedside of his dying mother – for it is the one moment in which he writes of a self he can neither understand nor control. It was horribly distressing for him – "She could no longer recognise us," he writes, and her mouth was full of tubes. When she died, he thought himself brave. He was the only family member who did not cry. After the funeral, he returned to school, thinking that everything was fine. But the next morning, in the school dormitory, he woke in floods of tears. "I had completely lost my bearings," he writes. "I went to stay with a friend for a couple of days… I would then recover my composure and return to school, only to be stricken by my grief once again and have to go and stay with someone else. It was awful."

As I say, we do not know Oscar. We can rummage through his life and choose the parts that make him resemble the South African miracle. Equally, we can bend and twist him until he looks like Mabegzo the gangster. Both were lost for being motherless. Both ploughed their sorrow into their bodies – "Sport was my salvation," Oscar writes. He can be made to resemble anything and everything South African – including the horror that Redi Thlabi so graciously laid on the page.

South Africa has actually done all right since the end of apartheid. It is true that our politics is increasingly corrupt, that people express discontent by throwing stones and burning things, that yawning inequalities cause much resentment. Less well known is that the income of the average black family has increased by about a third since the beginning of democracy; that 85% of homes are electrified compared with just over half on the last day of apartheid; that 85% of six-year-olds are in school now, whereas less than 35% were when apartheid ended. Even some forms of violence are way down – the murder rate, for instance, has dropped by a staggering 50% in the last 18 years.

Most of the poor still vote overwhelmingly for the ruling ANC, not because they have been duped, but because life has so obviously improved. It is nonetheless hard not to feel ambivalent about South Africa. Walk through inner-city Johannesburg on a Saturday morning and its spirit and its joy will leave you exhilarated. You can return home the same day to read that in a shack settlement 10 miles away a mob has set a person on fire. Spend a day in the city and you'll experience the kindness of innumerable strangers. And yet you will in all probability rub shoulders with an 11-year-old girl who expects to be raped.

South Africa has not learned both to love itself and to feel ambivalent about itself. It hasn't the courage to look itself squarely in the eye. That is why it invented Oscar the great on one day and Oscar the terrible the next. He will probably stand trial later this year. Whatever he has or has not done, it will be a terrible time for him. It would be good if, between now and then, South Africans could come to grasp that they are not Oscar and that Oscar isn't them.